珠江广州河段沉积物重金属潜在生物毒性风险

在珠江广州河段柱状沉积物重金属含量监测结果的基础上,对沉积物中重金属含量的垂向分布特征进行了分析,并运用SQGs法对沉积物重金属潜在生物毒性风险进行了评价。监测结果表明:在城区中心区上游河段,表层沉积物中重金属的含量比深层沉积物高;在城区中心区河段,大部分柱状沉积物中的重金属未表现出明显的变化规律;而在中心区下游河段,表现出表层沉积物中重金属含量比深层低的特点。沉积物中各种重金属元素之间均呈现较明显的正相关关系,表明在沉积物中这些重金属元素的含量具有共同变化的趋势。SQGs法的评价结果表明,Cu和Zn的潜在生物毒性较大,Pb和Cr的潜在生物毒性较小。从重金属毒性单位总和(∑TUs)的沿程分布可以看出,生物毒性风险由中心区上游到中心区下游整体上表现出低-高-低的分布特征。

Potential Biological Toxicity Risk of Heavy Metals in the Column Sediments from Guangzhou Section of the Pearl River

Based on the monitoring results of heavy metals in the column sediments,a systematic study was done on the vertical distribution characteristics of heavy metals in the sediments in Guangzhou section of the Pearl River,and SQGs was used to assess the potential biological toxicity risk of heavy metals in the Pearl River sediment.Results showed that heavy metal content in the surface sediments was higher than deep sediments in the upper-reaches of central area of Guangzhou,while heavy metal content in the surface sediments was lower than deep sediments in the lower-reaches of central area.However,there was no significant vertical distribution characteristics of heavy metals in sediments in the central area of Guangzhou.There was significant positive correlation between heavy metals,which showed heavy metals had the same distribution tendency in column sediments.The result of SQGs showed the potential biological toxicity risk of Cu and Zn was greater,but that of Pb and Cr was smaller.The longitudinal distribution characteristic of ∑ TUs showed that potential biological toxicity risk appeared the distribution characteristic of low-high-low from upper-reaches to lower-reaches.